Hydraulic motor



T- BUDZICH HYDRAULIC MOTOR Jam-11, 1966 5 Sheets-Sheet 1 Filed Dec. 4, 1963 llll MIN

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HYDRAULIC MOTOR Filed Dec. 4., 1963 3 Sheets-Sheet 2 j INVENTOR 740605Z a02/C# BY pmu/x MfA/A/A/r ff ,enea/Mara Jan. 11,1966 T. BUDzlcH 3,228,303

HYDRAULI C MOTOR Filed Dec. 4, 1963 3 Sheets-Sheet 5 INVENTOR ywef/w, 57% L Unitedl States Patent O 3,228,363 HYDRAULIC MOTOR Tadensz Budzich, Shaker Heights, Ohio, assignor to The Weatherhead Company, Cleveland, Ohio, a corporation of Ohio Filed Dec. 4, 1963, Ser. No. 328,019 16 Claims. (Cl. 91-198) This invention relates generally to piston type fluid motors and more particularly to axial hydraulic motors of the inclined axis type having a cylinder block rotating about an axis inclined to the output shaft.

In the manufacture of hydraulic devices of the general type to which this invention is related, the total cost of manufacture is, to a great extent, determined by the accuracy with which the various elements of the mechanism must be manufactured. In accordance With the present invention, the various elements are arranged so that exteremely close tolerances need not be maintained on all machined surfaces to prevent excessive leakage or other operating di'iculties. Although this invention is illustrated as embodied in a hydraulic motor, it should be understood that it is equally applicable to pumps and the term motor when used herein is intended to include both motors and pumps.

An inclined axis motor incorporating the present invention includes an output or reaction member journaled in a housing on a first axis and a cylinder block rotatable in the housing about a second axis inclined with respect to the first axis. A driving connection is provided between the reaction member and the cylinder block to cause them to rotate in unison. The cylinder block seats against a valve plate which functions to sequentially connect the cylinder bores to the input and output ports as the cylinder block rotates in the housing. The mounting of the cylinder block is arranged so that it is free of any forces which would tend to tip it with respect to the valve plate so that proper seating between the valving surfaces is maintained and leakage is minimized. Further, the valve plate is substantially hydraulically balanced to minimize deflection and allow a tight seal and minimize leakage under operating conditions.

Still further the parts are arranged so that if distortion of the motor housing occurs, causing changes of the valve plate position, the cylinder block merely moves to the correct position for optimum seating of the valving surfaces. In effect, the cylinder block is free to iloat with respect to the housing and output element so that it properly seats on the valve plate regardless of the position of the latter. Because of this free floating characteristic of the cylinder block it is not necessary to provide for precise location of the valve plate so the manufacturing tolerances thereof may be increased, and the production costs are minimized. A lighter Weight housing can also be used since the cylinder block remain-s aligned with the valve plate regardless of distortion of the housing under load.

Another feature of this invention results from a novel and improved arrangement of the piston rods which permits the use of lighter return springs Without full socket connections at the ends of the rods. The end of the rods at the reaction member are retained and locked in position by a retaining plate member and the piston ends of the connecting rods are free for substantial relative axial movement without risk of misalignment. Therefore, ligher piston return springs can be utilized than would be required if piston return were required in a positive manner under extremes of operating conditions. Here again, the various elements are arranged so that excessively close tolerances are not required with the result that manufacturing costs are minimized.

ICC

It is an important object of this invention to provide a novel and improved inclined axis hydraulic motor or pump wherein the cylinder block is freely floating to insure optimum sealing between the cylinder block and valve plate.

It is another important object of this invention to provide an inclined axis hydraulic motor including a cylinder block drive operable to position the cylinder block radially without imposing forces thereon tending to adversely affect the sealing thereof with the valve plate.

It is still another object of this invention to provide a novel and improved inclined axis hydraulic motor including a cylinder block drive journaled at both ends in selfaligning bearings and adapted to drive the cylinder block through a self-aligning connection.

It is another important object of this invention to provide an inclined axis hydraulic motor according to the last preceding object wherein the valve plate is substantially hydraulically balanced to minimize deflection and distortion thereof.

It is still another object of this invention to provide a novel and improved inclined axis hydraulic motor incorporating a piston rod connection loosely anchoring each piston rod at one end to the reaction member and allowing axial separation between the piston rod and the piston at the other end.

It is still another object of this invention to provide a novel and improved connecting rod mounting for reciprocating piston hydraulic motors which utilizes a simplified structure to retain the piston rod in the associated eiement.

It is still another object of this invention to provide a novel and improved inclined axis hydraulic motor wherein th'e elements are proportioned and arranged to minimize the necessity of close tolerance high cost manufacturing operations.

Further objects and advantages will appear from the following description and drawings wherein;

FIGURE l is a side elevation in longitudinal section of an inclined axis hydraulic motor incorporating this invention;

FIGURE 2 is an enlarged end view of the cylinder block looking away from the valve plate;

FIGURE 3 is an enlarged end view of the valve plate looking away from the cylinder block;

FIGURE 4 is an enlarged end view of the opposite end face of the valve plate;

FIGURE 5 is an enlarged fragmentary section taken along 5 5 of FIGURE 4;

FIGURE 6 is a fragmentary section illustrating the structure of one of the transfer sleeves connecting the valve ports of the valve plate to the supply and return ports of the housing;

FIGURE 7 is an enlarged fragmentary section illustrating the mounting of the connecting rods in the reaction member; and,

FIGURE 8 is an end elevation of the housing illustrating the position of the supply and return ports in the housing.

Referring to the drawings in greater detail, the preferred embodiment of a hydraulic motor incorporating this invention includes a housing assembly including a main housing 10 and an end housing 11 connected together by bolts 12 and sealed by an O-ring seal 13. A reaction member 14 is journale'd in the end housing 11 on spaced antifriction bearings 16 and 17. The bearing 16 of the tapered roller type particularly suited for carrying both axial and radial l-oads and the bearing 17 is primarily arranged .to provide radial load carrying capacity. However, the two bearings cooperate to axially lix the reaction member 14 in the end housing 11 for rotation about a iirst axis indicated at 18. The end of the reaction member 14 projects beyond the end of the end housing and is provided with a key 19 or other suitable structure for drivingly connecting the reaction member 14 to the load when the device is usedgas-a motor or to a power source when the device is used as a pump. A seal assembly 21 is mounted in the end housing 11 by a snap ring 22 to prevent leakage along the reaction member from the interior of the housing.

A valve plate 23 is mounted in the end of housing 10 opposite reaction member 14 and is formed with a radial valving face 24 engaging one end of a cylinder block 26. The cylinder block 26 is formed with a plurality of symmetrically arranged cylinder bores 27 which extend parallel with respect to each other. Preferably, an odd number of cylinder bores 27 are provided, as illustrated in FIGURE 2. A piston 28 is located in each cylinder bore 27 and is connected to the reaction member 14 by a piston rod 29.

A drive assembly is connected between the reaction member 14 and cylinder block 26 to insure synchronous rotation of these two members. This drive includes a rst bevel gear 31 mounted in the reaction member 14 and secured in place with a crosspin 32. A drive member 33 is formed with a bevel gear 34 meshing with the gear 31. The drive member 33 is journaled at its ends for rotation about a second axis 36 inclined with respect to the first axis 18 and intersecting such axis at the center of a spherical bearing 38 which fits into mating spherical sockets 39 and 41 in the bevel gear 31 and drive member 33 respectively. This spherical bearing provides for both axial and radial location of the bevel gear 34 of the drive member 33 and allows free swiveling between the drive member and reaction member. The opposite end of the drive member 33 extends through an axial bore 37 in the cylinder block and is radially journaled in a roller bearing 42 which is carried in a bearing cage 43.

A thrust bearing 44 is positioned ybetween the end of .the bearing cage 43 and a thrust washer 46 which in turn is seated against a shoulder 47 on the drive membe-r 33. This thrust bearing operates to axially position the drive member with respect to the bearing cage 43 and the spherical bearing 38. Clearance is provided at 48 between the thrust' washer 46 and the cylinder block 26 to positively prevent any contact between these bearings and the cylinder block.

The bearing cage 43 is formed with an outer circumferential land 49 which engages the inner wall of an axial blind bore 51 in the Valve plate 23. This provides radial support and positioning for ,the bearing cage 43, but since the land 49 has a relatively short axial length or may be made spherical, the bearing cage is free to align itself with the drive member 33 even if the bore 51 is not exactly aligned with the axis 36. A pin 52 extends into bores formed in the valve plate 23 and bearing cage 43 to prevent rotation therebetween. Sullicient clearance, however, is provided so that the pin 52 will not prevent the bearing cage from freely aligning itself with the axis 36.

An adjusting pin 53 extends through a bore 54 in the valve plate 23 and a bore 56 in the housing 10 and engages at its outer end an adjusting screw 57 threaded into .the housing 10. A seal 58 at the junction of bores 54 and 56 prevents leakage along the adjusting pin 53. The inner end of the adjusting pin 53 engages the bearing cage to axially locate the bearing cage with respect to the main housing. External adjustment of the adjusting screw 57 provides for axial adjustment of the drive member 33 to allow the proper clearances for the spherical bearing 38 and between the gears 31 and 34. Therefore, it is not necessary to manufacture these parts to extremely close tolerances since simple means are provided for adjusting for variations in manufacturing 4 9 tolerances in the drive system and to compensate for any wear which may occur.

The drive member 33 extends through the bore 37 in cylinder block 26 with clearance to a location adjacent the valve plate end thereof. At this point adjacent the thrust washer 46 the drive member 33 and the cylinder blocks 26 are formed with interengaging splines 59 which provide the driving connection between the drive member and the cylinder block. The splines 59 are formed with a sufficiently loose t to permit some rocking and misalignment between the axis 36 of rotation of the drive member 33 and the axis of rotation of the cylinder block 26. Because the splines 59 are loose, it is impossible for forces to be transmitted from .the drive member 33 to the cylinder block 26 which would tend to lift or tip the cylinder block with respect to the valve face 24. Therefore, the cylinder block 26 is free to properly seat against lthe valving face 24 even if the valving face 24 is not exactly perpendicular to the axis 36. This freedom to seat minimizes leakage and provides eicient operation of the valve system. The splines 59 provide the radial location of the cylinder block with respect to the axis 36 and valve plate 23. The slight radial freedom due to the loose spline connection does not adversely affect the :operation of the motor since the radial positioning of the valving surfaces is not extremely critical. However, by making the spline teeth spherical, .the radial clearance can be eliminated while retaining the limited universal alignment characteristics.

Each of the cylinder bores 27 is connected to an associated cylinder port 61 at the valve face of the cylinder block 26. This communication is provided through stepped bores 62 and 63 which are joined by a radial shoulder 64. A return spring 66 extends between the shoulder 64 and a radial surface 67 formed on the piston 28 to resiliently urge the piston in a direction toward the reaction member 14.

Referring now to FIGURES 3 and 4, the valve face of the valve plate 23 is formed with two arcuate valve ports 68 and `69 which in turn are connected to inlet and outlet ports 71 and 72, respectively. A transition section 73, illustrated in FIGURE 5, connects the associated valve ports and inlet and outlet ports.

Radially inwardly of the valve ports 68 and 69 the valve rface 24 is formed with an annular groove or recess 74 which is drained through a plurality of symmetrically arranged drain passages 76. Similarly, an external annular groove 77 is formed around the valve ports 68 and 69 and is open to the main cavity of lthe motor through a plurality of radial grooves 78. The grooves 74 and 77 cooperate to limit the sealing area of the engaging surfaces of the valve plate 23 and the cylinder block 26. The valve face 24 must be accurately formed and the mating surface of the cylinder block 26 must also be accurately formed so that proper sealing will -be achieved. However, the opposite face 79 of the valve plate 23 and the mating face 81 in the housing 10 do not have to be manufactured to extremely close tolerances since they merely serve to axially locate the valve plate in the main housing 10 and the cylinder 'block 26 is free to seat against the valving surface 24 even when that surface is not exactly perpendicular to the axis 36. Further, if the main housing 10 distorts under load and 4allows the valve plate 23 to move with respect to the axis 36 there will be no ditculty since the cylinder block 26 is free to move to the proper posltion with respect to the valve plate 23.

To provide substantial hydraulic balancing of the valve plate, transfer tubes are utilized in each of the ports 71 and 72. The transfer tube 82 in the inlet port 71 is illustrated in FIGURE 6 `and. it should be understood that an identical tube would be located in the outlet port 72. The transfer tube 82 etxends from the inlet port 71 into a mating bore 83 formed in the main housing 10 and connected to the motor inlet 84. The transfer tube 82 is provided on its outer periphery with a rst seal 86 sealing with the inlet port 71 and a second seal 87 sealing With the bore 83 and the transfer tube is free to float with respe-ct to both the valve plate 23 and the housing 10.

Preferably, the area of the inlet port 71 is equal to about 90% of the area of the associated valve port 68 and is located so that it is substantially co-axial with the center of area or centroid of the valve port 68. Therefore, hydraulic reaction tending to urge the valve plate toward the end wall 81 is balanced to a substantial degree by an opposing hydraulic reaction in the opposite direction acting along the same line of action. Therefore, the valve plate is not subjected to any substantial force tending to warp or bend the plate and the valve face 24 will remain llat. The low unbalanced force serves to retain the valve plate in position in the housing 10.

In addition, the cylinder block is subject to an unbalanced force tending to bias it into sealing contact with the valve plate. The cylinder ports 61 have an area smaller than the cross sectional area of Jthe cylinder bores, and this area diterential is greater than the area of the cylinder block between ports 61 exposed to the high pressure of the valve plate port. These areas are chosen so that there is a net force biasing the cylinder block against the valve plate so that the force of engagement beween the valve face 24 and the associated end of the cylinder block 26 will increase as a direct function of the pressure lbeing sealed. This insures that adequate sealing is maintained at lall times. The springs 66 produce a reaction force on the cylinder block which augments the hydraulic sealing force and also insures that the cylinder block remains seated against the valve plate so that proper sealing is provided when the motor starts.

The torque required to rotate the cylinder lblock 26 with the reaction member 14 is relatively small compared to the output torque of the motor. However, any torque transmitted through the bevel gears 31 and 34 ends to urge the drive member in a direction tending to align it with the i'irst axis 18. This drive reaction is carried by the bearing cage 43 and valve 23 and is not transmitted to the cylinder block 26. The location of the loose spline 58 substantially adjacent to the valve plate 23 insures that the centering or radial locating forces .applied to the cylinder block will not tend to produce any substantial tipping tforce thereon.

Referring now to FIGURES 1 and 7, each piston rod 29 is formed with :a spherical end 91 which seats in a spherical recess 92 in piston 28. The pistons 28 are each provided with `a bore 93 extending from the spherical recess 91 to a conical section 94 which in turn extends to a larger second bore 96. The engagement of the spherical end 91 in the spherical recess 92 results in a self-centering connection which carries the driving forces from the .piston to the reaction member and sufficient clearance is provided to permit the necessary swiveling.

In the event that the motor operates in a condition where it is driven by the load or otherwise rotates under conditions where the iiuid forces and the force of the springs 66 do not move the pistons 28 toward the reaction member with sufficient velocity to maintain contact with the connecting rods 29, the spherical end 91 merely moves to the right as viewed in FIGURE 1 out of engagement with the spherical recess. However, the elements are proportioned so that the spherical end 91 will remain within the hollow portions of the pistons 28 and be guided back into its proper seated position b-y the bores 93 and 96 and the conical section 94. Since it is not necessary to maintain absolute contact between the pistons and the associated connecting rods, lighter springs 66 can used than would otherwise be necessary.

'Iihe reaction member end of each of the piston rods 29 is formed with a structure best illustrated in FIG- URE 7. The reaction member 14 -is formed with a spherical recess 97 for each of the connecting rods 29. The adjacent end of the conecting rod is formed with a head having a mating spherical end 98 which is normally in engagement with the wall of recess 97 to provide a swivel connection for the transmission of the driving forces to the reaction member 14.

To insure that the heads 11i@ of the piston rods remain in the associated recesses 97, a retaining plate 99 is mounted on the reaction member 14 by a snap ring 101. An opening 162 having a diameter smaller than the maximum diameter of the head 100 is formed in the retaining plate adjacent to each of the recesses 97. Therefore, each head 109 is loosely but positively retained in the associated recess 97 after this mechanism is assembled. The center of curvature of the spherical recess 97 is located within the opening of 102 so that swiveling of the connecting rod 29 does not require excessive clearance between the opening 102 and the connecting rod 29. Preferably, the connecting rod 29 is provided with a short section 103 of reduced diameter adjacent the opening 102. However, the opening 102 must have a diameter slightly larger than the main diameter of the connecting rod to permit assembly.

Bleed passages 104 and 106 are formed in the bearing cage 43 and cylinder block 26, respectively, and cooperate with the drain passages 76 to insure that the pressure does not build up in the central zone between the cylinder block and valve plate. The ports 196 are connected through the clearance between the drive member 33 and the cylinder block bore 37 to the main cavity. Ports 107 and 168 are provided `in the main housing 10 and end housing 11 to drain the main cavity.

In operation the fluid flows through the motor inlet 84 and associated transfer tube 82 to the inlet Valve port 68. As the cylinder block 26 rotates cylinder ports 61 move into communication with the inlet valve port 68 and the fluid flows into the associated cylinder bores 27 filling such bores as the associated pistons 28 move in a direction away from the valve plate. As the cylinder block continues to rotate the cylinder ports 61 thereafter move into communication with the outlet ports 69 which in turn communicates with the outlet port 72 and associated transfer tube 82. During this phase of operation the associated pistons move in a direction toward the valve plate and pump the fluid out of the associated cylinders.

By arranging the cylinder block 26 so that it is free to oat with the valve plate and so that it is not subjected to any forces which would tend to tip it with respect to the valve plate, ecient valving is maintained even though the valving surface 23 is not precisely positioned with respect to the axis 36. Further, the provision of hydraulic balancing of a substantial portion of the forces on the valve plate eliminates distortion or bending thereof and cooperates with the floating feature to insure proper valving operation under all conditions of operation. The simplified structure of the connecting rods with a simple and low cost retainer on the reaction member and no positive retention 0n the piston end allows reduced manufacturing costs and simplifies assembly without impairment of operating eiciency, flexibility or durability.

Although the preferred embodiment of this invention is illustrated, it is to be understood that various modifications and rearrangements may be resorted to without departing from the scope of the invention as defined in the following claims.

What is claimed is:

1. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a rst axis, a valve plate in said housing having a valving surface disposed about a second axis intersecting rst axis and inclined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder block substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means between said pistons and said reaction member, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled for rotation about said second axis and drivingly connected to said reaction member for rotation therewith, and driving connection means between said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member, said driving connection means being constructed and arranged to permit said cylinder block to tilt and to radially locate said cylinder block with respect to saiddrive member and said valve plate to maintain sealing contact between said porting surface and said valving surface, the engagement of said valving surface and said porting surface providing the sole guiding surface preventing tilting of said cylinder block with respect to said valving surface.

2. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a first axis, a Valve plate in said housing having a valving surface disposed about a second axis intersecting first axis and inclined with respect thereto, a cylinder block in said housing, a porting surface seated against said valving surface, cylinder bores in said cylinder block sustantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means between said pistons and said reaction member, means urging said cylinder block into sealing engagement With said valving surface, a drive member journaled for rotation about said second axis and drivingly connected to said reaction member for rotation therewith, driving connection means between said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member said driving connection means being constructed and arranged to permit said cylinder block to tilt and to radially locate said cylinder 'block with respect to said drive member and said valve plate to maintain sealing contact between said porting surface and said valving surface, and fluid passage means operable to provide substantial balancing of the hydraulic forces on said valve plate, the engagement of said valving surface and said porting surface providing the sole guiding surface preventing tilting of said cylinder block with respect to said valving surface.

3. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a rst axis, a valve plate in said housing having a valving surface disposed about a second axis intersecting first axis and inclined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder block substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means between said pistons and said reaction member, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled for rotation about said second axis and drivingly connected to said reaction member for rotation therewith, and a loose spline means interconnecting said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member, said loose spline means being constructed and arranged to permit said cylinder block to tilt and to radially locate said cylinder block with respect to said drive member and said valve plate to maintain sealing contact between said porting surface and said valving surface.

4. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotationabout a first axis, a valve plate in said housing having a valving surface substantially perpendicular to a second axis intersecting first axis and inclined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder blocks substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means between said pistons and said reaction mem'- ber, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled in bearings at each end for rotation about said second axis and drivingly connected to said reaction member for rotation therewith, and driving connection means intermediate said bearings between said cylinder block and said drive member to rotate said cylinder block synchronously with rotation of said reaction member, said drive connection means permitting limited tilting of said cylinder block with respect to said drive member while guiding said cylinder block radially with respect to said drive member and said valve plate to maintain sealing contact between said porting surface and said valving surface, the engagement of said valving surface and said porting surface providing the sole guiding surface preventing tilting of said cylinder block with respect to said valving surface.

5. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a first axis, a valve plate in said housing having a valving surface substantially perpendicular to a second axis intersecting first axis and inclined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder blocks substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means interconnecting said pistons and said reaction member, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled in bearings at each end for rotation about said second axis and drivingly connected to said reaction member for rotation therewith, and loose spline means intermediate said bearings interconnecting said cylinder block and said drive member to rotate said cylinder block. synchronously with the rotation of said reaction member, said spline means permitting limited tilting of said cylinder block with respect to said drive member while guiding said cylinder block radially with respect to said drive member and said valve plate to maintain sealing contact between said porting surface and said valving surface.

6. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a first axis, a valve plate in said housing having a valving surface substantially perpendicular to a second axis intersecting first axis and inclined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, said cylinder block being free to shift radially with respect to said valve plate, cylinder bores in said cylinder blocks substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means interconnecting said pistons and said reaction member, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled on said reaction member and on said Valve plate for rotation about said second axis and drivingly connected to said reaction member for rotation therewith, and driving connection means between said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member, said drive connection means permitting limited tilting of said cylinder block with respect to said drive member while guiding said cylinder block radially with respect to said drive member and said valve plate to maintain sealing contact between said porting surface and said valving surface, the engagement of said valving surface and said porting surface providing the sole guiding surface preventing tilting of said cylinder block with respect to said valving surface.

7. A hydraulic motor comprisingr a housing, a reaction member journaled in said housing for rotation about a first axis, a valve plate in said housing having a valving surface substantially perpendicular to a second axis intersecting first axis and inclined with respect thereto, a

cylinder block in said housing having a porting surface seated against said valving surface, said cylinder block being free to shift radially with respect to said valve plate, cylinder bores in said cylinder blocks substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means interconnecting said pistons and said reaction member, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled on said reaction member and on said valve plate for rotation about said second axis and drivingly connected to said reaction member for rotation therewith, and loose spline means interconnecting said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member, said spline means permitting limited tilting of said cylinder block with respect to said drive member while guiding said cylinder block radially with respect to said drive member and said valve plate to maintain sealing contact between said porting surface and said valving surface.

8. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a first axis, a valve plate in said housing having a valving surface substantially perpendicular to a second axis intersecting first axis and inclined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder blocks substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means interconnecting said pistons and said reaction member, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled at one end on a self-aligning bearing on said reaction member and at its other end on a self-aligning bearing on said valve plate for rotation about said second axis, gear means interconnecting said drive member and said reaction member for synchronous rotation, and driving connection means between said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member, said driving connection means permitting tilting between said drive member and cylinder block to maintainsealing contact between said porting surface and said valving surface, said engagement of said valving surface and said porting surface providing the sole guiding surface preventing tilting of said cylinder block with respect to said valving surface.

9. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a first axis, a valve plate in said housing having a valving surface substantially perpendicular lto a second axis intersecting first laxis and inclined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder blocks substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means interconnecting said pistons and said reaction member, means urging said cylinder block into sealing engagement with said valving surface, a drive member journaled at one end on a self-.aligning be-aring on said reaction member -and at its other end on a self-aligning bearing on said valve plate for rotation about said second axis, gear means interconnecting said drive member and said reaction member for synchronous rotation, and a loose spline means interconnecting said cylinder block and said drive member adjacent said valve plate to rotate said cylinder block synchronously with the rotation of said reaction member while permitting said cylinder block to tilt and shift radially with respect to said drive member and said valve plate to maintain sealing contact between said porting surface and said valving surface.

10. A rotary hydraulic mechanism comprising a housing, a reaction member journaled on said housing for rotation about a first axis, a drive mem-ber journaled in said housing for rotation about a second axis inclined relative to said first axis, means connecting said drive mem-ber and reaction member for synchronous rotation, a non-rotating valve plate in said housing, a cylinder block in said housing formed wi-th a plurality of parallel -cylinder bores .symmetrically arranged around said second axis, a piston in each cylinder bore, a piston rod operatively connected between each piston and said reaction member whereby each piston reciprocates in its associated bore when said cylinder block and output element rotate, a semi-spherical recess in said reaction member for each piston rod, a head on each piston rod formed with a mating end surface which is semi-spherical in shape and engages the wall of the associated recess, and a retaining plate mounted on said reaction member adjacent said recesses, an opening in said plate adjacent to each recess through which the associate-d piston rod extends with clearance, the center of curvature of each recess being located in the adjacent opening, said heads having a diameter greater than the diameters of said openings, inter-engaging valving surfaces on said valve plate and cylinder block, and a loose spline drive between said drive member and cylinder block preventing relative rotation therebetween while radially locating said `cylinder block with respect -to said valve plate.

11. A piston and cylinder uid pressure mechanism comprising a cylinder block, a reaction member, a piston slidable in said cylinder block, a piston rod connected between said piston and reaction member, a semi-spherical reoess in said reaction member, a head on said piston rod formed with a mating end surface which is semispherical in shape and engages the wall of said recess, a retaining plate secured to said reaction member and formed with an opening adjacent to said recess through which said piston rod extends with clearance, said head having a dia-meter greater than the diameter of said opening and having an axial length less than the spacing between said opening and Said recess to allow limited free axial movement of said head out of engagement with `said recess, and means urging said mating end surface toward said wall of said recess maintaining contact therebetween during normal conditions of operation.

12. A piston and cylinder uid pressure mechanism comprising a cylinder block, a reaction member, a plurality of pistons slidable in said cylinder block, a piston rod connected between each piston and said reaction member, .a semi-'spherical recess in said reaction member for each piston rod, a head on each piston rod formed with a mating .end surface which is semi-spherical in shape and engages the wall of the associated recess, a retaining plate secured to said reaction member and formed with an opening adjacent to each recess through which the associated pist-on rod extends with clearance, the center of curvature of each recess being located in the Iassociated opening, sai-d head-s having a diameter greater than the diameter of said openings and having an axial length less than the spacing between said opening and said recess to allow limited free axial movement of said head ou-t of engagement with said recess, and springs urging each piston in a direction toward said reaction member maintaining the mating end surface of the associated piston rod in engagement with said wall of the associ-ated recess under normal conditions of operation.

13. A piston and cylinder fluid pressure mechanism comprising a cylinder block, a reaction member, a piston slidable in said cylinder, a piston rod connected between sa-id piston and reaction member, a semi-spherical recess in said reaction member, a head on one end of said piston rod formed with a mating end surface which is semi-spherical in shape and engages the wall of said recess, a retaining plate secured to said reaction member and lformed with an lopening adjacent to said recess through which said piston rod extends with clearance,

the center of curvature of said recess being located in said opening, said head having a diameter greater than the diameter of said opening and having an axial length less than the spacing between said opening and said recess to allow limited free axial movement of said head cut of engagement with said recess, said pis-ton being formed with an elongated passage terminating at its inner end in a semi-spherical bearing surface, a second mating surface on said piston rod engaging said end surface, said passage guiding said second mating surf-ace linto engagement with said bearing surface, and spring means urging said piston toward said reaction member normally maintaining said head in bearing contact with said recess.

14. A hydraulic motor comprising a housing dening a iluid chamber therein, inlet and outlet openings at one end of said housing, a reaction member journaled in the other end of said housing for rotation about a rst axis, a valve plate non-rotatably secured in said housing adjacent said openings and having a valving surface substantially perpendicular to a second axis intersecting said first axis and inclined with respect thereto, inlet and outlet valving ports formed in said valving surface, inlet and outlet openings in said Valve plate open t said inlet and outlet valving ports respectively, transfer tube members interconnecting associated inlet and outlet openings of said housing land valve plate, said transfer tubes being freely axially movable with respect to said valve plate, said inlet and outlet openings in said valve plate having an effective area slightly less than the area of said valve plate ports to substantially hydraulically balance said valve plate in said housing, a rotatable cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder block substantially parallel to said second axis, said cylinder bores having inlet ports hav-ing an area substantially less than that of said cylinder bores and adapted to interconnect with the valving ports on said valving surface whereby uid pressure in said cylinder bores biases said cylinder block into sealing contact with said valve plate, a piston within each of said cylinder bores, each of said pistons having a head portion and a skirt portion extending away from said valve plate, spring means within each of said cylinder bores biasing said pistons away from said valve 4 plate, a spherical recess in each of said pistons adjacent said head end thereof, connecting rod means interconnecting said pistons and said reaction member, said connecting rods having spherical ends engaging said spherical recess on said pistons, spherical recesses on said reaction member corresponding to each of said cylinder bores, each of said connecting rods having a spherical head portion seated within one of said recesses on said reaction member, said head portion having a diameter substantially larger than that of the remainder of said connecting rod, a retaining plate secured to said reaction member adapted to loosely retain said connecting rods in seating engagement with said recesses, said retaining plate having openings in alignment With each of said recesses on said reaction member -to receive each of said connecting rods therethrough, said openings having a diameter greater than that of the remainder of said connect-ing rod and less than that of said connectingy rod heads, a first bevel gear on lsa-id rection member, a spherical bearing mounted on said first bevel gear, a drive member journaled at one end on said spherical bearing, a second bevel gear on said drive member adjacent said spherical bearingand mating with said rst bevel geary to rotate said drive member synchronously with rotation of said reaction member, an axial recess in said valve plate adapted to receive the other end of said drive member, a bearing cup carrying a bearing for journal-ing the other end-of said drive member and being Iarranged to be selfaligning within said recess on said valve plate member,

loose spline means interconnecting said cylinder block 'and said drive member adjacent said valve plate t-o rotate said cylinder block synchronously with a rotation of said reaction member, said loose spline means permitting limited tilting lof said -cylinder block with respect to said guide member while guiding said cylinder blo-ck radially with respect t-o said drive member and said valve plate to permit said cylinder block to be self-aligning with respect to said valve plate to maintain sealing contact between said porting surface and said valving surface regardless of axial misalignment between sa-id driving member and the true axis of rotation of said cylinder block. 15. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a first axis, a valve plate in said housing having a valving surface disposed about a second axis intersecting said first axis and in-clined with respect thereto, a cylinder block in said housing having a porting surface seated against said valving surface, cylinder bores in said cylinder block substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means between said pistons and said reac-tion member, a drive member journaled at one end on said reaction member for rotation about said sec-ond axis and drivingly connected to said reaction member for rotation therewith, a bearing on said valve plate journalling the other end of said drive member, external adjustment means for said Ibearing to adjust the axial clearance for said drive member between said bearing and said reaction member, and driving connection means between said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member.

16. A hydraulic motor comprising a housing, a reaction member journaled in said housing for rotation about a rst axis, a Valve plate in said housing having a valving surface disposed about a second axis intersecting said ii-rst axis and inclined with respect thereto, a cylinder block in said housing having .a porting surface seated against said valving surface, cylinder bores in said cylinder block substantially parallel to said second axis, pistons within each of said cylinder bores, connecting rod means between said pistons and said reaction member, rnc-ans urging said cylinder block into sealing engagement with said valving surface, a drive member journaled at one end on said reaction member for rotation about said second axis, bevel gear means drivingly connecting said drive member to said reaction member forrotation therewith, radial and thrust bearing means, said valve plate journalling the other end of said drive member, said bearing means including a bearing housing nondrotatably mounted on said valve plate, external adjustment means for adjusting the position of said Abearing housing t-o adjust t'he axial clearance for said drive member at said bearing means and said reaction member, and driving connection means between said cylinder block and said drive member to rotate said cylinder block synchronously with the rotation of said reaction member.

References Cited by the Examiner UNITED STATES PATENTS 1,158,554 11/1915 Pratt 91--198 1,785,355 12/1930 Lawser 91-198 2,177,008 10/ 1939 Snade-r et al. 103--162 2,445,281 7/1948 Rystrum 91-198 2,708,879 5/ 1955 Van Meter 92-57 2,735,407 2/1956 Boron 91-198 2,990,784 7/ 1961 Wahl'mark 91-198 3,037,489 6/ 1962 Douglas 91--198 SAMUEL LEVINE, Primary Examiner.

FRED E. ENGELTHALER, Examiner.

P. E, MASLOUSKY, Assistant Examiner. 

1. A HYDRAULIC MOTOR COMPRISING A HOUSING, A REACTION MEMBER JOURNALED IN SAID HOUSING FOR ROTATION ABOUT A FIRST AXIS, A VALVE PLATE IN SAID HOUSING HAVING A VALVING SURFACE DISPOSED ABOUT A SECOND AXIS A CYLINDER BLOCK IN SAID HOUSING HAVING A PORTING SURFACE SEATED AGAINST SAID VALVHOUSING HAVING A PORTING SURFACE SEATED AGAINST SAID VALVE ING SURFACE, CYLINDER BORES IN SAID CYLINDER BLOCK SUBSTANTIALLY PARALLEL TO SAID SECOND AXIS, PISTONS WITHIN EACH SAID CYLINDER BORES, CONNECTING ROD MEANS BETWEEN SAID PISTONS AND SAID REACTION MEMBER, MEANS URGING SAID CYLINDER BLOCK INTO SEALING ENGAGEMENT WITH SAID VALVING SURFACE, A DRIVE MEMBER JOURNALED FOR ROTATION ABOUT SAID SECOND AXIS AND DRIVINGLY CONNECTED TO SAID REACTION MEMBER FOR ROTATION THEREWITH, AND DRIVING CONNECTION MEANS BETWEEN SAID CYLINDER BLOCK AND SAID DRIVE MEMBER TO ROTATE SAID CYLINDER BLOCK SYNCHRONOUSLY WITH THE ROTATION OF SAID REACTION MEMBER, AND DRIVING CONNECTION MEANS BEING CONSTRUCTED AND ARRANGED TO PERMIT SAID CYLINDER BLOCK TO TILT AND TO RADIALLY LOCATE SAID CLYINDER BLOCK WITH RESPECT TO SAID DRIVE AND SAID VALVE PLATE TO MAINTAIN SEALING CONTACT BETWEEN SAID PORTING SURFACE AND SAID VALVING SURFACE, THE ENGAGEMENT OF SAID VALVING SURFACE AND SAID POURING SURFACE PROVIDING THE SOLE GUIDING SURFACE PREVENTING TILTING OF SAID CYLINDER BLOCK WITH RESPECT TO SAID VALVING SURFACE. 